This invention relates to a simple and reliable system for protecting a power reactor from the effects of an accident or the occurrence of abnormal conditions in the reactor.
The invention also relates to a primary heat transport system for a power reactor which is capable of providing emergency core coooling for the reactor.
The invention further relates to a cooling system for a liquid-metal-cooled, multiple-coolant-loop, fast-breeder power reactor which ensures effective heat removal from the reactor even though one of the coolant loops is disrupted.
It is obvious, of course, that the cooling system for a power reactor should ensure to the utmost extent possible heat removal from the reactor core following an accident or the occurrence of abnormal conditions in the reactor. Thus an Emergency Core Cooling System (ECCS) must be provided supplementing the main Heat Transport System (HTS) to provide cooling in the event the main HTS becomes inoperative. The ECCS and the HTS together must positively ensure that there will always be the necessary heat removal capability to protect the reactor. This capability must exist for a broad spectrum of possible accident conditions from equipment failures to loss of electrical power to complete loss-of-coolant accidents. Not only must this protection exist, it must be provided by as simple and reliable a system as possible in order that its own effectiveness be undiminished by functional unreliability.
No particular preferred system for emergency core cooling of liquid-metal-cooled reactors has been indicated by existing reactors or reactor designs. For example, natural circulation within the main Heat Transport System such as on the French reactor, Rapsodie, protects against equipment failure and loss of electrical power but not against loss of coolant. Other systems used heretofore include a separate natural circulation auxiliary system as in the German design, Na 2, pony motors and doubly-contained piping as on the Fermi reactor, and auxiliary forced circulation system as on the Sefor and SRE-PEP reactors.